A typical scroll compressor of this kind is disclosed, for instance, in U.S. Pat. No. 4,568,256 of Edward S. Blain. The scroll compressor disclosed in said publication relates to a compressor for separating a lubricant from refrigerant by comprising: first and second scrolls having interfitting vanes defining a pumping interface including a movable fluid-containing pocket; means for moving one of said scrolls in a closed, non-linear path relative to the other to cause said pocket to move along said interface; a plurality of radially inner outlets partially in at least one of said scrolls and opening to said interface; a radially outer inlet opening to said interface; an open conduit within said one scroll extending from said outlet to said interface remote from said outlet; and means associated with said outlet for inducing rotary motion in a fluid therein to cause centrifugal separation of lubricant from the fluid in the vicinity of said conduit.
On the other hand, another conventional hermetic type scroll compressor is shown in cross section in FIG. 3. As shown in FIG. 3, it is constructed of a hermetic container defined by a cylindrical body 1, a bottom plate 2, and a top cover 3. Fixed and orbiting scrolls 26, 24 are disposed within the container. In order to smoothly feed a cooling lubricant for maintaining a fluid tightness, i.e., seal between the fixed scroll 26 and the orbiting scroll 24, a lubricant feeding capillary tube 11 is provided adjacent a suction pipe 19, and the lubricant contained within refrigerant gas discharged from discharging outlet 27 is drained to the lower part of the container through a capillary tube 15.
There occurs an improved fluid tightness of the fixed scroll 26 and the orbiting scroll 24, when cooling lubricant is fed. However, there has been a problem that although discharging pressure is increased according to the improvement of said fluid tightness, because a pressure difference with suction pipe 19 becomes increased, the cooling lubricant is excessively fed through the lubricant feeding capillary tube 11.